NIH-supported projects in the Chemistry Department at Case Western Reserve University require routine access to an X-ray Crystallographic structure determination unit. The Department currently operates a Syntex P21 diffractometer which is 12 years old, suffers from appreciable down-time and is no longer state-of- the-art, with the result that it is inadequate for the volume of samples to be run. Consequently, there is a considerable delay in obtaining vital structural information for several important organic synthesis projects, leading to retarded progress and delays in publication. It is proposed to purchase a Nicolet R3m/V which will be used in determination of crystal structures of: conducting inorganic complexes and their precursors; transition metal silicon compounds; binuclear transition metal chelate complexes; organosilicon compounds; natural products, their derivatives, and precursors used in their total synthesis.